This invention relates to the manufacture of stents. The invention provides a new method of processing stents in at least one liquid bath, to a jig for supporting stents during such processing, processing equipment incorporating the new jig, and to stents so manufactured.
Stents used for implantation into veins or arteries are typically lattice-walled tubes which are extremely fragile. The basic manufacturing process typically leaves burrs on the walls of the stent which must be removed prior to use. The removal of these burrs is typically performed electrolytically (e.g. by electropolishing).
Hitherto, in order to remove such burrs, an electrode held on a jig has been inserted into one end of the stent and the stent has been immersed in an acid bath for electrode erosion of the burrs. Because of the fragility of the stent it is necessary that the electrode used should make contact with the interior of the stent, and electrodes used have hitherto taken the form of a bent wire or a pair of expanding tweezers which are inserted into the stent end. In an attempt to obtain a uniform treatment of the stent it has been necessary to remove it from the electrode during the course of any active treatment and to replace the stent so that the electrode is located at its other end. This is time consuming. Because stents are so fragile, they are apt to become damaged during this reversal process. Considerable skill is required in order to remove and replace the stents in this way. Furthermore, of course the fact that the electrodes are located at each of the two ends for approximately half of the processing operation will entail that the ends of the stent are processed in a different manner from of the remainder of its length.
Analogous problems arise if it is desired to electroplate a stent.